Narrative:

On may/xx/93, a near midair collision (250 ft horizontally) occurred between air carrier X and an small transport Y. Both aircraft were at 8000 ft and on IFR flts. The cause of the near midair collision is the failure of the ATC communications system, wescom 921. The controller's altitude and heading changes were not received by either aircraft. The faulty air traffic communications equipment has been failing for at least 2 1/2 yrs. This latest failure almost resulted in an actual collision. Callback conversation with reporter revealed the following: the reporter stated no action was going to be taken by facility management until the captain of air carrier X called and filed an near midair collision. Reporter said numerous ucr's had been filed on the radio equipment to no avail. Reporter said the near midair collision received press coverage and the reporter called his congressman and senator to complain about the radio equipment and the number of failures at the facility. Due to congressional action the facility will receive new radio equipment in oct/93. Supplemental information from acn 241097: en route from ind-evv, level at 8000 ft on V11, 45- 50 DME northeast pxv VOR, visibility was about 7 mi. ATC had been quiet since our check on. We then heard our flight number once. We answered twice but no response back. A short (30-60 seconds?) ATC said, do you have traffic at 11 O'clock, but no flight or aircraft number. We looked and saw a twin engine plane on a collision course with us. We climbed immediately to avoid a collision. We missed by about 200 ft vertically with no lateral separation. We would have hit without this evasive action. We then heard ATC call the other aircraft. Aircraft answered them and their conversation reflected previous attempts by ATC to contact them that they didn't hear. Aircraft was on our frequency but we heard no attempts by ATC to call aircraft or us other than what I mentioned above. We stopped our climb at about 8500-8600 ft and told ATC what we had done. They responded with words indicating they had tried to call us. From my discussions with them on the ground, they had equipment problems.

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Original NASA ASRS Text

Title: ACR X HAD NMAC LTSS WITH SMT Y BECAUSE OF ATC EQUIP PROB RADIOS FAILED. EVASIVE ACTION TAKEN. FACILITY RADIO FAILURE IS AN ONGOING PROB.

Narrative: ON MAY/XX/93, A NMAC (250 FT HORIZLY) OCCURRED BTWN ACR X AND AN SMT Y. BOTH ACFT WERE AT 8000 FT AND ON IFR FLTS. THE CAUSE OF THE NMAC IS THE FAILURE OF THE ATC COMS SYS, WESCOM 921. THE CTLR'S ALT AND HDG CHANGES WERE NOT RECEIVED BY EITHER ACFT. THE FAULTY AIR TFC COMS EQUIP HAS BEEN FAILING FOR AT LEAST 2 1/2 YRS. THIS LATEST FAILURE ALMOST RESULTED IN AN ACTUAL COLLISION. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: THE RPTR STATED NO ACTION WAS GOING TO BE TAKEN BY FACILITY MGMNT UNTIL THE CAPT OF ACR X CALLED AND FILED AN NMAC. RPTR SAID NUMEROUS UCR'S HAD BEEN FILED ON THE RADIO EQUIP TO NO AVAIL. RPTR SAID THE NMAC RECEIVED PRESS COVERAGE AND THE RPTR CALLED HIS CONGRESSMAN AND SENATOR TO COMPLAIN ABOUT THE RADIO EQUIP AND THE NUMBER OF FAILURES AT THE FACILITY. DUE TO CONGRESSIONAL ACTION THE FACILITY WILL RECEIVE NEW RADIO EQUIP IN OCT/93. SUPPLEMENTAL INFORMATION FROM ACN 241097: ENRTE FROM IND-EVV, LEVEL AT 8000 FT ON V11, 45- 50 DME NE PXV VOR, VISIBILITY WAS ABOUT 7 MI. ATC HAD BEEN QUIET SINCE OUR CHK ON. WE THEN HEARD OUR FLT NUMBER ONCE. WE ANSWERED TWICE BUT NO RESPONSE BACK. A SHORT (30-60 SECONDS?) ATC SAID, DO YOU HAVE TFC AT 11 O'CLOCK, BUT NO FLT OR ACFT NUMBER. WE LOOKED AND SAW A TWIN ENG PLANE ON A COLLISION COURSE WITH US. WE CLBED IMMEDIATELY TO AVOID A COLLISION. WE MISSED BY ABOUT 200 FT VERTICALLY WITH NO LATERAL SEPARATION. WE WOULD HAVE HIT WITHOUT THIS EVASIVE ACTION. WE THEN HEARD ATC CALL THE OTHER ACFT. ACFT ANSWERED THEM AND THEIR CONVERSATION REFLECTED PREVIOUS ATTEMPTS BY ATC TO CONTACT THEM THAT THEY DIDN'T HEAR. ACFT WAS ON OUR FREQ BUT WE HEARD NO ATTEMPTS BY ATC TO CALL ACFT OR US OTHER THAN WHAT I MENTIONED ABOVE. WE STOPPED OUR CLB AT ABOUT 8500-8600 FT AND TOLD ATC WHAT WE HAD DONE. THEY RESPONDED WITH WORDS INDICATING THEY HAD TRIED TO CALL US. FROM MY DISCUSSIONS WITH THEM ON THE GND, THEY HAD EQUIP PROBS.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.